When I was in high-school I got really ill. My parents took the tough-love approach and I'm so glad they did or I think I'd still be ill over a decade later. I have a good life!

My advice is to do things you know are good for you even if they don't seem appealing in the moment. Things that are enjoyable for you. A walk, a trip to the gym, 1 hour reading a book, bake a cake: whatever you enjoy. It's a huge part of learning to take care of yourself.

Also have a "bad day protocol" because you will undoubtedly have bad days. The key is to prevent a bad day from turning into a bad week and old habits. Make a short list of things that are still achievable on a bad day. My 3 things were: Get out of bed, get washed and dressed, leave the house once (for any reason). Do this so that even on a bad day you will still have accomplished something and won't feel like you've "failed" and go into a depressive, demotivated spiral.

Best of luck! You can do this! (but I think you know that. The fact you're here asking questions proves it!)